According to the current state of technology, the lubrication of transmission components by means of oil-bearing shafts is known. The known shafts possess at least one axial bore hole, through which a liquid medium can flow. Radial bore holes are further provided in the shaft for radially, outwardly directing the flow of the liquid medium. These radial bore holes communicate with the axial bore hole, allowing the flow of the liquid medium.
Such oil-bearing shaft is described in the applicant's patent application DE 103 33 432. It includes bore extending coaxially and/or axially parallel relative to the longitudinal axis of the shaft, as well as no less than two oil-bearing channels located to direct oil flow outwardly from the bore these two or more channels are separate from each other. In order to employ several oil-bearing channels in a comparatively thin shaft, the channels are constructed on the interior wall of the shaft in the form of channels, which are open throughout their longitudinal extension, and separated and sealed against each other by a pipe that is inserted into the shaft interior. At least one radial lubrication bore hole and/or supply bore hole is provided in the shaft according to DE 103 33 432 A1.
An oil-bearing shaft, which, according to the current state of technology, has a radial supply bore hole. This shaft at a high rotational speed, has a problem due to centrifugal force, which creates a pressure opposing the lubrication pressure, such that only an insufficient amount of medium and/or lubricating oil can be supplied through the shaft through to radial oil supply bore holes. This results in the pressure within the axial bore hole dropping, relative to the increasing distance to the mediums' supply point and/or the oil supply bore hole.
The oil supply's dependency on rotational speed can, in the case of an automatic transmission with lubrication supplied by the drive shaft, result in the fact that with increased rotational speed, the last oil user, i.e. a planetary gear, will adversely receive an insufficient amount of lubricating oil.